Brake appliance



Dec. 22,v 1942. J. BERGER 2,305,759 v BRAKE APPLIANCE Filed Nov. l5.1939 v 2 Sheets-Sheet l Attorney Dec. 22, 1942. J, BERGER 2,395,759

BRAKE APPLIANCE Filed Nov. 13, 1939 2 Sheets-Sheet 2 f7.2 I d? f 3 @l 33g 3/ 28 g l' ZI Patented Dec. 22, 1942 BRAKE APPLIANCE .lulius Berger,Berln-Wilhelmsruh, Germany; vested in the Alien Property CustodianApplication November 13, 1939, Serial No. 304,225 In Germany August 3,1939 2 Claims.

brakes and in many cases double brakes for each i wheel ofthe carriageare required. The brake volume of such braking plants, having forinstance four wheels and eight brakes, however, is too large to bebrought to action directly by the foot of the pilot.

In all cases in which large brake pressures are required, the subjectmatter of the invention is of great advantage according to which thebrake pressure medium is supplied by a power driven pump to the brakeand in the pipe carrying the pressure medium a control mechanismmaintaining the brake pressure proportionally to the force applied tothe brake pedal is provided.

Now, it would appear to be evident to use for these purposes thehydraulic arrangement always present in aircrafts, but this again oftenwould lead to the greatest difficulties for the reason that thehydraulic arrangement in the aircraft is not available for use as soonas the driving motors break down. Therefore, a hydraulic accumulatorwould have to be built in to warrant the safe appliance of the brakeeven on break down of the motors. By mounting a hydraulic accumulator,however, the weight of the aircraft would considerably be increasedagain which under all circumstances must be prevented if possible.

A current circuit which by mounting an accumulator would be independenton the break down of one or the other driving motor always is present inaircrafts so that by the use of this circuit for obtaining the requiredbrake pressure the best guarantee would be given for a safe operation ofthe brakes without increasing the weight of the aircraft.

In the accompanying drawings one construction according to the inventionis shown by way of example.

In these drawings:

Fig. 1 shows a diagrammatic view of a brake arrangement according to theinvention and Fig. 2 represents a sectional detail of the controlmechanism.

An electromotor 2 arranged in the circuit I drives a pump 3 to whichpressure medium, for instance oil, is supplied from a tank 5 by Way of apipe 4. Pipes 6 and 1 formed as by-pass pipes branch from the pump 3 andare connected again to the pump 3 by way of a pipe 9. From the bypasspipes 6 and 1 pipes I0 and II respectively branch off which lead topipes I4 and I5 respectively connected to the brakes of the wheels I2and I3 respectively arranged in twin form. In each of th'e by-pass pipes6 and 1 a control device, generally .designated IIS, is arranged in thedirection of flow behind the corresponding pipes III and I Irespectively. This control device IS is shown in detail in Fig. 2 and,as may be seen from this gure, a valve formed as a piston is arranged ina cylinder I1. The piston I6 is controlled by springs I9 and I9. Theother end of the springs I9 and I9 bears against a second piston 2i),the rod 2l 0f which may be controlled by the pedal 22 and 23respectively. The valve proper is formed by a projection 24 of thepiston I8 and this projection again is subjected to the action of a weakspring 25. Between the pipes I0 and II and the corresponding controldevice I6 each of the bypass pipes 6 and 1 is connected to the lowerportion of the cylinder I1 by way of a passage 26 so that the pressuremedium supplied by way of the by-pass pipes 6 and 1 may act upon theundersurface of the piston I3 and move the latter upwardly against thepressure of the springs I9 and I9.

The cylinder I1 is surrounded by an insulating ring 21 carrying a switch28. The insulating ring 21 is acted upon by a spring 29, the other endof which bears against a shoulder 30 of the piston I1. The rod 2| issurrounded by a cap 3| a projection 32 of which may press the button 33of the switch 28. If the brake is released, the switch 28 disconnectsthe circuit of the electromotor 2, whereas, if the brake operation isinitiated by pressure upon the pedal 22 or 23, the circuit of theelectromotor 2 is closed immediately by the pressure of the projection32 upon the button 33, whereby the pump 3 is caused to act in order tosupply the pressure medium by way of the pipes 6 and 1 or 6 or 1respectively.

As soon as pressure is applied to the pedal 22 or 23, the correspondingpiston I8 0f the control device I6 after overcoming the pressure of thesprings I9, I9 moves downwardly, whereby, also after overcoming thepressure of the spring 25, the projection 24 of the piston I8 closes theby-pass pipe 6 or 1 respectively, so that now by way of the pipes 6, I0,I4 or 1, II, I5 respectively the full pressure exerted by th'e pump 3acts upon the brakes of the wheels I2 or I3 respectively. By reducingthe pressure exerted upon the brake pedal 22 or 23 respectively, thepiston I8 moves upwardly for a more or less larger amount sov that itsprojection 24 more or less uncovers the opening of the correspondingby-pass pipe 6 orI l` so that a larger or smaller amount of the pressuremedium only flows in circulation without acting upon the brakes, wherebythe power applied to the brake pedal always is maintained proportionallyto the brake pressure and whereby, moreover, the desired braking of theone or the other pair of Wheels l2 and I3 respectively may be obtainedWhat I claim is:

1. A brake appliance comprising brakes, a

